Pin-tumbler lock



M. c. MAXWELL. PIN TUMBLER LOCK. APPLICATION FILED SEPT-2, 1921.

Patented July 11, 1922.

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attain/e1 MAXWELL C. MAXWELL, 0F STAMFORD, CONNECTICUT, ASSIGNOR TO THE YALE 9: TOWNE MANUFACTURING COMPANY, OF STAMFORD, CONNECTICUT.

PIN-TUMBLER LOCK.

naaaset T 0 all whom it may concern Be it known that I, MAXWELL C. MarwnLL, a citizen of the United States, and a resident of Stamford, in the county of Fairlield and State of Connecticut, have invented certain new and useful Improvements in Pin-Tumbler Locks; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to improvements in pin tumbler locks and more particularly to means for safeguarding the tumblers,the object of the invention being to provide the plug and cylinder members of the lock with efficient armor which will prevent damage to the tumblers with the use of a boring tool.

With this object in view, the invention consists in certain novel features of construction and combinations of parts as hereinafter set forth and pointed out in the claims.

In the accompanying drawings Figure 1 is a front view of a lock embodying my improvements. Figure 2 is a longitudinal sectional view partly in elevation. Figure 2 is a view in elevation of the armored cylinder construction, taken at right angles to Figure 2. Figure 3 is a view of the armored plug. Figure l is a sectional view on the line H of Figure 3, and Figures 5 and 6 are views of modifications.

The cylinder of a pin tumbler look is shown at 1 and provided at its front end with a face plate 2,said cylinder having therein bores 3 for the accommodation of spring pressed drivers such as commonly employed in locks of this type. The plug a is mounted to turn in the cylinder and is provided with bores 5 to receive pin tumblers.

The forward end portion of the plug is reduced to form a shank 6 having a head 7 at, its front end whereby recesses 8-8 are formed. The shank 6 and its head 7 receive an armor head 9 of hardened steel, the latter being so formed that when placed in position on the plug, it will have dovetail connection with the same. The armor head 9 is provided at its front end with an annular flange 10 which is seated in a recess 11 in the face plate of the cylinder. Instead of form- Specification of Letters Patent.

Patented July 11, 1922.

A pplication filed September 2, 1921. Serial No. 497,939.

ing the shank 6 with recesses 88 to receive parts of the armor head 9 for effecting dovetail connection of the latter with the plug as shown in Figure 3, the plug may be made with a shank 12 and the armor head 9 provided with a socket 13 to receive the same, said armor head being secured to the shank by means of pins 14, as shown in Figure 5.

The cylinder 1 is also provided with an armor head 15 of hard metal and may have clove-tail connection with the cylinder as indicated at 16, the construction being the same as the connection of the armor head 9 to the plug 4 shown in Figure 3, or if desired the connection of the cylinder armor head 15 may be effected as shown in Figure 6, wherein pins 1% are employed for securing the parts together in the same manner as shown in Figure 5.

lVith my improvements the tumblers will be protected from injury by a boring tool inserted either through the front end portion of the cylinder or through the front end of the plug.

Having fully described my invention what I claim as new and desire to secure by Let ters-Patent, is:

l. A pin tumbler lock comprising a cylinder and aplug, said plug comprising two parts having interlocking connection with each other, one of said parts made of hardened metal and constituting an armor head.

2. In apin tumbler lock, the combination with the cylinder, of a plug mounted therein and including a hardened steel head form ing part of the same and located in the cylinder.

3. In a. pin tumbler lock, the combination with a. cylinder, of a plug mounted therein and having a reduced portion, and a hardened steel head dovetailed to said reduced portion and constituting a part of the plug.

t. A pin tumbler lock comprising a cylinder and plug, a portion of each consisting of a hardened metal armor head, the hardened steel armor head of the plug located in the hardened steel armor head of the cylinder.

5. In a pin tumbler lock, the combination of a cylinder having a shank, and an armor head secured to said shank and forming part of said cylinder.

6. In a pin tumbler lock, the combination with a cylinder having a shank and a plug specification in the presence of two subscribhavmg a shank, of anarmor head secured lng wltnesses.

to the shank of the cylinder and formin I part of the latter, and an armor head seemed MAXVELL MAXNELL' 5 tothe shank of the plug and forming a part Vitnesses:

of the latter. RAYMOND H. SULLIVAN,

In testimony whereof, I have signed this CHAS. A. BERRY. 

